In a triangular ABC, the lengths of the three sides are 15, 17 and 8 respectively. What is the area of the triangular ABC? Such as title

In a triangular ABC, the lengths of the three sides are 15, 17 and 8 respectively. What is the area of the triangular ABC? Such as title

Because 8 ^ 2 + 15 ^ 2 = 17 ^ 2, triangle ABC is a right triangle s = 15 * 8 / 2 = 60
Hope to adopt

In triangle ABC, if a = 8, B = 17, C = 15, then ∠ ABC=

Because a ^ 2 + C ^ 2 = 289, B ^ 2 = 289,
So a ^ 2 + C ^ 2 = B ^ 2,
And ∠ ABC is exactly the angle between edges a and B, and C is the oblique edge, so it satisfies the Pythagorean theorem, then ∠ ABC = 90 degrees

In the triangle ABC, the known angle a = 60 degrees, B: C = 8:5, the inscribed circle area is 12 π, and the triangle area is calculated

Answer: the area of triangle ABC = 40 √ 3, let the radius of inscribed circle = R, the center of circle is O, make the vertical lines OE, of and og of AC, BC and ab respectively through O, and the vertical feet are e, F and g respectively, connecting OA, OB and OC. Let AC = b = 8x, ab = C = 5x, π * R ^ 2 = 12, π r = 0e = of = og = 2 √ 3, ∠ a = 60 °, OAE = ∠ OAG = 30 °, Ao = 2R = 4

How to find the area of a triangle in a plane rectangular coordinate system?

There are two methods: 1. Direct calculation (needless to say, you know how to calculate it. Fill the triangle of the plane rectangular coordinate system into a square that can calculate its area, and then draw it, and you will definitely calculate it (square area minus excess area)

How to calculate the area of a triangle in a plane rectangular coordinate system?

You mean to know the coordinates of the three points of the triangle and then calculate the area of the triangle, right
You can use the universal formula. Only if you understand the meaning, you can calculate the area of any polygon according to the coordinates
The principle of the formula is: make two arbitrarily connected points perpendicular to the Y axis (horizontal axis) and add the connecting line of two points to form a trapezoid. According to the area calculation formula of the trapezoid, the area can be calculated, and then calculate the next point in the same way, in the order of 1 point and 2 points, 2 points and 3 points, 3 points and 4 points, 4 points and 1 point. Turn one circle, and add the area to get the area of the polygon (remember that the order must be uniform, so that the length and area will have negative values, and all areas will not increase)

The car runs at the speed of 20m / s on a straight road. There is a situation in front of it that requires emergency braking. The acceleration of braking is 8 meters per square second. Braking The car runs at the speed of 20m / s on a straight road, and emergency braking is required in front of it. The braking acceleration is 8m per square second. After braking, it can be regarded as uniform deceleration and linear motion. Calculate the speed of the car after braking for three seconds

The braking movement needs to consider the time from the beginning of braking to stopping,
In the title, it is known that the initial speed V0 = 20m / s and the acceleration a = - 8m / S2, so it takes (0-20) / (- 8) = 2.5s for the car to stop